Display screen or portion thereof with transitional graphical user interface



FIG. 1 is a display screen or portion thereof with transitionalgraphical user interface showing a first image in a sequence;

FIG. 2 is a second image in a sequence thereof;

FIG. 3 is a third image in a sequence thereof; and,

FIG. 4 is a fourth image in a sequence thereof.

The broken line showing of a display screen or portion thereof andportions of a graphical user interface is included for the purpose ofillustrating portions of the article and forms no part of the claimeddesign; the broken line showing of a mobile device is included for thepurpose of illustrating environmental structure and forms no part of theclaimed design.

The process or period in which one image transitions to another forms nopart of the claimed design.

CLAIM The ornamental design for a display screen or portion thereof withtransitional graphical user interface, as shown and described.